[GSOC] Userland System V Shared Memory / Semaphore / Message Queue implementation

[grigore larisa <larisagrigore@xxxxxxxxx>]

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Hello,

My name is Larisa Grigore and I am student in the second year at a master
program "Internet
Engineering" from Polytechnics University of Bucharest, Romania, Computer
Science and
Engineering Department.

Currently I am working at a research project for master program. The
project is about "High Availability".  We try to keep a system, that runs
over a microkernel
from L4 family, alive no matter what happens with its components. The
detected faults are segmentation faults, deadlocks and killed threads. From
the point of view of recovery, two possible options are provided:
restarting an address space or restoring it from some checkpoint. The user
can order classic and incremental checkpoint and use those two types in
correlation with fork mechanism. In order to build the HA module, memory
management and fork with copy-on-write mechanisms were implemented.
High Availability features, previously developed for native applications
running on top of microkernel,  were extended for Linux operating system. A
kernel module was implemented to support fault detection (deadlocks,
segmentation faults and killed processes) and recovery. The process can be
restarted from zero or from a specific checkpoint.
The project aims to cover cases where Android fails to restore properly an
application. After studding frequent android application failures, we
concluded that High Availability support can be useful for some classes of
applications too.